Storytelling Science

Sex Education

Amitabha Mukerjee

I was recently listening to a conversation on sex between a teenager
son and his progressive father:

Son: "The girls in my class have started to behave rather strangely!"
Father: "Oh, they have crossed puberty, and now their sexual instincts
are aroused." [Mother pauses her chay preparation to listen. Dad can't be
trusted.]
Son: "But why?"
Father: "Around the age of thirteen, their bodies start making
estrogen, which is a hormone that ultimately triggers these sexual
feelings. In boys, testosterone that does the same thing."
Son: "But why does this happen?"
Mother [from Kitchen]: "Ashish - have you finished your maths homework
yet?"

But seriously, why is it that beyond a certain age, boys and girls
begin to find each other interesting? Why do some features in a woman
make her more attractive to men, and vice versa? What makes the sexual
act, two sweaty bodies rubbing each other, so much fun?

Why is sex fun?

These questions are important not only because they make for great
conversation with your teenaged children (and your mother-in-law), but
also because they are part of the many questions that define our
identity as humans.

What can science tell us about sex? The branch of science
that deals with "deep" answers to such questions is Evolutionary
Biology, which studies how species evolve. A "shallow" answer is that
once the organism is able to survive, the body produces
hormones that cause sexual interest. The "deep" answer is that
we are all creatures of our genes, and those genes that cause interest
in the opposite sex propagated and survived. Those others, which
didn't find the opposite sex interesting, rapidly became extinct.

Many of us, brought up the way we have been, are somehow uncomfortable
with such answers. However, if you think about it, the logic is
unassailable. Consider two women, Arti and Bina: the genes in Arti
make her interested in men, but Bina's don't. The chances are good
that Bina's genes will disappear in the next generations. Even if
Bina's interest levels are lower, ultimately there will be fewer
people carrying her genes in the coming generations. Over time, the
whole population will gravitate towards showing great interest in the
opposite sex. If it hadn't, you and I would not be here.

Sex Appeal

Now let us consider the next question: What features of a female does
a male find attractive?

First, a symmetric body is indicative of complete and wholesome
development. Second, the skin of the face is singularly indicative of
the wear and tear the body has suffered. It is no wonder then, that
facial symmetry and a "glowing" skin are two primary measures of
physical beauty - not only in humans, but across many species.

Another important issue was that in the millions of years when our
bodies (and our brains) evolved, the big question was infant survival.
Even in our grandparent's generation, it was common to have only three
or four from a dozen babies survive beyond the first year. In periods
of food scarcity, the mother wouldn't have enough milk - and an
under-nourished child was more susceptible to disease and death. But
if the mother's body had a lot of fat, then her body could break it
down to make milk for the child. For the male, seeking to maximize
the probability that his gene would survive, it was important to
select a mate who was high on fat. For women, seeking to attract the
best males, it was important to advertise their fat reserves. Using
the same Arti-Bina logic as above, you can incontrovertibly show
that:

Females will develop fat reserves that are prominently displayed
on their bodies, (e.g. breasts and buttocks),

Males will develop strong genetic preferences for women with such
features.

The fact is that despite being cultured twenty-first century
Hindustan-Times-readers, we are all carrying the baggage of our many
million years of evolution. This evolutionary program is etched into
our brains, and expresses itself in our sexuality.

Sexual Signaling

There are many such questions that scientists think they have answers
for. For example, why do male peacocks have such extravagant
tail-feathers? The fact is that such a tail is a serious handicap in
terms of agility, especially in the presence of predators. That a
male peacock can survive to adulthood despite such disadvantages tells
the female that he is strong and will make a good father. It is what
biologists call an "honest" signal, for it comes at a heavy cost. The
male behaviour has also evolved to accommodate this, which is why he
struts off his tail in the famous peacock dance display.

When you started reading this article, you were wondering what this
topic is doing on the Science Page of the paper. By now, if you are
like many of my friends and well-wishers, you are perhaps wondering
what this person is doing outside a mental institution. But please do
not take this lightly, there is matter for much thought in all of
this.

Do yourself and the teenagers around you a favour. Discuss these
points with them, and if it turns interesting, do drop me a line
letting me know!